How the polls went wrong – and why they are still worth listening to

The preliminary results of the British Polling Council inquiry into the general election polls have been published. The findings give the industry plenty to think about.

According to the inquiry team, led by Professor Patrick Sturgis of Southampton University, the main reason the final polls did not reveal a decisive Tory lead was that polling samples – the people who took part in the surveys – were not sufficiently representative of the voting population. For example, the team highlighted evidence from the polls they examined that in the oldest age group, those aged 65 and over, too many participants were at the younger end of the scale, and not enough were aged over 75.